For the sewing of trouser pieces, i.e. two pieces of fabric adapted to be stitched together along a pants leg or the like in the formation of a pair of trousers, an edge-true stitching of the pieces is required. The term "edge-true" is used herein to refer to the stitching of a substantially linear seam along trouser legs or the like with the two pieces preferably aligned along the edge at which the seam is to be formed at a given distance from this edge. This distance must be held constant and the two fabric pieces must lie in registry along the edge to be stitched and a substantially rectilinear seam must be formed for effective edge-true stitching.
For the feeding of fabric pieces to be stitched together along a seam at a sewing location in a sewing machine, it is known to provide an edge guide device laterally of the sewing station which is provided with a substantially vertically oriented linear guide surface along which the edges of the pieces are held as the pieces are guided past the sewing location. The fabric is guided by hand or by compressed air in an edge-true relationship along this guide surface.
The guide element can be provided with guide plates which extend transversely to the guide surface and at least partially cover the fabric pieces at their edge regions, i.e. overlie the latter, and serve to separate the pieces from one another until they reach the stitching location. This ensures a better guidance of each individual fabric piece and prevents bunching thereof at the guide surface.
It has been proposed fairly recently to facilitate the feeding of the fabric pieces along the guide surface, by providing a pair of guide rollers which, although not driven, engage the fabric and impart a force component thereto in the direction of the guide surface and hence enable the self-feeding effect of the sewing machine to advance the fabric past the stitching location in edge-true relationship. Such a device is described for example in German Utility Model (Gebrauchsmuster) No. 7.330.505.
With such a device, the sewing machine operator need merely bring the fabric pieces into contact with the guide surface and into the region of the stitching location, whereupon the self-feeding effect ensures edge-true seaming of the two pieces. In this manner the leg portions of a pair of trousers, having straight leg seams, can be sewn with self-feeding and self-guidance of the fabric parts, requiring a minimum of handling by the operator.
However, this arrangement is ineffective for the sewing of waistband and pocket or other intricate regions of the trousers. The pocket parts of such devices cannot be effectively brought under the guide plates and, since they are generally previously attached to the fabric pieces, the plates interfere with the manipulations by the operator to sew these portions of the trousers. However, after the pocket parts, waistband portions and like complicated parts of a pair of trousers are stitched, it is desirable to again use the plates for guiding the fabric parts during further leg-seam stitching.
In German Utility Model (Gebrauchsmuster) No. 7.319.362, there is described a workpiece guide device in which a preferably pneumatically driven plate is swingable about a vertical axis and can be rotated into the guiding position to serve for the guiding and separation of the fabric pieces during the legs seam stitching of the trousers. Moreover, this plate can be readily swung into an inoperative or ineffective position when the pocket portions, waistband and like parts of the trousers are to be stitched. Consequently, the pocket parts can be sewn under manual control with simple guidance of the fabric pieces by hand without interference by the guide and separating plates while the leg parts can be stitched with the use of the guide plates under self-guidance and self-feeding of the fabric segments.